key physical features include the highest peak in south east asia Mount Kinabalu in sabah malay borneo over 4000 meters, i've climbed it so from personal experience its high!!
Oldest rainforest in world in Peninsular Malaysia, Taman Ne Gara (means National Park).
Largest collection of islands making up Philippines.
One of top dive sites in the world in sabah, malay borneo, Sipadan, great reef, hundreds of turtles!